X-ray image processing apparatuses for cardiovascular disease have been developed as image guide apparatuses used for angiographic examination and interventional treatment which examines and treats arteries and veins in the whole body. X-ray image processing apparatuses process images obtained by X-ray imaging in the state where a contrast medium is injected in blood vessels, and display image data on an image display unit or apparatus.
In, for example, coronary angiography, a contrast medium is injected through a catheter inserted at the proximal of a coronary artery. Arterial examination measures the degree of stain of a blood vessel, and tissue examination measures the degree of stain of myocardial tissue. In the latter examination, there is known a method for measuring the flow in myocardial tissue, namely, perfusion, on the basis of the degree of stain.
In these types of measurement, it is necessary to set a region of interest (ROI) on an image and acquire time-density information relating to the ROI. In a conventional method for determining a ROI, the operator has to operate the mouse or buttons of a computer by means of the Graphical User Interface (GUI) or the like, while simultaneously observing an X-ray image. However, the operation may be troublesome to perform, and the operation performed may vary depending upon the skill of the operator. In addition, it is not desirable to perform the operation in a clean room such as a room where intravascular treatment is being performed. There have been needs to automate ROI setting, and hence demands have arisen for some technical developments.